Credit

Caption

Desmids and amoeba. Polarised light micrograph of a Netrium sp. desmid (left) and Arcella sp. testate (shelled) amoeba (round). Desmids are a common group of freshwater single-celled algae that have intricate cell walls. Arcella sp. amoeba are found in freshwater ponds and puddles. Magnification: x200 when printed 10 centimetres wide.